Photoprotective/cosmetic compositions comprising cinnamonitrile-substituted polyorganosiloxanes/polyorganosilanes

Abstract

Topically applicable sunscreen/cosmetic compositions well suited for enhanced photoprotection of human skin and/or hair against the damaging effects of UV-A and UV-B irradiation, particularly solar radiation, comprise a photoprotecting effective amount of a novel cinnamonitrile-substituted polyorganosiloxane/polyorganosilane.

What is claimed is: 
     
       1. A cinnamonitrile-substituted polyorgano-siloxane/polyorganosilane compound having the formula (3): ##STR23## in which the radicals R', which may be identical or different, are each a C 1  -C 8  alkyl radical or a phenyl radical; and the radical A is a monovalent radical bonded directly to a silicon atom and which has the following formula (4): ##STR24## wherein X 1  is a cyano radical or an alkoxycarbonyl radical COOR 1  in which the radical R 1  is (i) a C 1  -C 20  alkyl radical, (ii) a C 2  -C 20  hydroxyalkyl radical, or (iii) a divalent radical --Y-- having the following formula (5): ##STR25## in which R 2  is a hydrogen atom or a C 1  -C 4  alkyl radical, p is an integer ranging from 0 to 10, inclusive; m is 0 or 1; the --CH 2  -- endgroup is directly bonded to a silicon atom; X 2  is a hydrogen atom or an optionally substituted phenyl or C 6  -C 10  aryl radical; n is an integer ranging from 0 to 2, inclusive; the radicals X 3 , which may be identical or different, are each a C 1  -C 8  alkyl radical or a C 1  -C 4  alkoxy radical, with the proviso that, when the radicals X 3  are alkoxy radicals, two adjacent radicals X 3  (n=2) may together form an alkylidenedioxy group in which the alkylidene moiety contains 1 or 2 carbon atoms; and X 4  is a hydrogen atom or a divalent radical --Y--, with the proviso that, if X 4  is a hydrogen atom, then X 1  is necessarily a radical COOY in which m is zero. 
     
     
       2. A polyorganosiloxane/polyorganosilane compound as defined by claim 1, wherein formula (3), the radicals R' are methyl, ethyl, propyl, n-butyl, n-octyl or 2-ethylhexyl radicals. 
     
     
       3. A polyorganosiloxane/polyorganosilane compound as defined by claim 2, said radicals R' being methyl radicals. 
     
     
       4. A polyorganosiloxane/polyorganosilane compound as defined by claim 1, wherein the formula (3), X 1  is a cyano radical or a radical COOR 1  in which R 1  is a methyl or ethyl radical, or a radical --Y--. 
     
     
       5. A polyorganosiloxane/polyorganosilane compound as defined by claim 1, wherein the formula (3), X 2  is hydrogen or a phenyl radical. 
     
     
       6. A polyorganosiloxane/polyorganosilane compound as defined by claim 1, wherein the formula (3), X 3  is methoxy radical (n≠0) or is hydrogen (n=0). 
     
     
       7. A polyorganosiloxane/polyorganosilane compound as defined by claim 1, wherein the formula (3), a divalent radical --Y-- is on the 4-position of the benzene ring. 
     
     
       8. A polyorganosiloxane/polyorganosilane compound as defined by claim 1, wherein the formula (3), in a divalent radical --Y--, p ranges from 1 to 3. 
     
     
       9. A polyorganosiloxane/polyorganosilane compound as defined by claim 1, wherein the formula (3), in a divalent radical --Y--, R 2  is hydrogen or a methyl radical. 
     
     
       10. A topically applicable sunscreen/cosmetic composition adopted for the photoprotection of human skin and/or hair, comprising a photoprotecting effective amount of a polyorganosiloxane/polyorganosilane compound as defined by claim 1, in a cosmetically acceptable vehicle, carrier or diluent therefor. 
     
     
       11. The sunscreen/cosmetic composition as defined by claim 10, said cosmetically acceptable vehicle, carrier or diluent comprising at least one fatty phase or at least one organic solvent. 
     
     
       12. The sunscreen/cosmetic composition as defined by claim 10, comprising an oil-in-water or water-in-oil emulsion. 
     
     
       13. The sunscreen/cosmetic composition as defined by claim 10, comprising from 0.1% to 20% by weight of said photoprotecting compound. 
     
     
       14. A method for protecting human skin and/or hair against the deleterious effects of ultraviolet irradiation, comprising topically applying thereto an effective amount of the sunscreen/cosmetic composition as defined by claim 10. 
     
     
       15. A method for protecting human skin and/or hair against the deleterious effects of solar radiation, comprising topically applying thereto an effective amount of the sunscreen/cosmetic composition as defined by claim 10.